accelerator pump

7 replies to this topic
  • sbohanon

Posted January 14, 2001 - 02:11 PM


just cleaned the carb on my yz, accelerator pump was all gunked up as expected. how much stroke should the actuating rod have? seems like 1/16th of an inch or less. it runs fine with no hesitation.

btw, the 51t sprocket has some extra pep on dry pavement, spins the wheel easily on the cinders. can't wait to get it in the dirt!

  • Boit

Posted January 14, 2001 - 05:46 PM


That 1/16 of an inch rod stroke sounds about right. That's what I noticed on my 426. Evidently, when that center rod is pushed down, the large diameter neoprene diaphram supplies the volume of gas.

  • blbainb

Posted January 14, 2001 - 07:26 PM


What year bike is it? The '98 and '99 bikes have a different carb design which exposes the push rod to the elements. It's normal for the accel pump to get 'gunked up'. Some use grease/electrical tape to form a boot to protect the rod and reduce the build up.

  • uplate

Posted January 14, 2001 - 07:37 PM


Nice tip blbainb, thanks.

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  • sbohanon

Posted January 15, 2001 - 03:35 AM


it's a 1999 and has the boot over the actuating rod. the grease idea sounds real good. i did notice however that the brass guide pressed into the carb body has a split in it to compensate for the press fit. this split probably allows more dirt into the pump than the loose fitting boot.

  • Guest_Guest_*

Posted January 15, 2001 - 03:49 AM


Do you think to much movement of the accelerator pump rod would cause a hesitation? I've gone way up on my pilot jet (50) and I still have a hesitation. I'm thinking i may be from the accelator pump pushing too much fuel. Is this possible?


  • James_Dean

Posted January 15, 2001 - 06:15 AM


Try a change of needle clip. Probably to a richer clip position. What is the needle code and clip position now?

  • Guest_Guest_*

Posted January 15, 2001 - 07:07 AM


James Dean,

Its stock all the way. I think 4th clip?


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